Particulate matter (PM10) is a major air pollutant affecting air quality and human health. This study assessed PM10 concentrations, composition, and health risks in 12 educational centers in Ilo, Peru, during the summer of 2017-2018. A total of 36 PM10 samples were collected, identifying eight potentially toxic elements (As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn) using inductively coupled plasma optical emission spectroscopy (ICP-OES). PM10 levels were higher in the urban area (UP), with one episode exceeding the Peruvian standard (100 µg m-3) and six surpassing the World Health Organization (WHO) limit (50 µg m-3). Significant differences were found for As (0.013-0.016 µg m-3) and Zn (0.06-0.058 µg m-3) (p < 0.05). Source analysis identified metal smelting (As, Cd, Pb, Zn) and vehicular traffic (Ni, Mn) as major contributors. The health risk assessment showed Cu exceeded the safety threshold (hazard quotient (HQ) > 1) in both zones, with a hazard index (HI) of 4.71 (fenced industrial area (FI)) and 5.48 (UP). The carcinogenic risk (CR) for As and Cd was within acceptable limits (CR < 1 × 10-4) but requires monitoring. These findings highlight the need for pollution control strategies to protect the health of children in urban and industrial environments.

This study evaluated concentrations of particulate matter with aerodynamic diameter ≤ 10 µm (PM10) and potentially toxic elements (PTEs) in three urban zones of Ilo, a coastal city in southern Peru, during the cold season (July–October 2022). The cold season is characterised by greater atmospheric stability and a lower mixing layer height, which favours pollutant accumulation and scenarios of higher potential exposure. Three contrasting zones were analysed: commercial (UCZ), industrial (UIZ), and peripheral (UPZ), through daily PM10 sampling and analysis of six PTEs (Al, As, Ba, Cu, Mn, and Zn). The UPZ recorded the highest mean PM10 concentration (23.8 ± 11.6 µg/m ³ ), with 5% of daily records exceeding the World Health Organization (WHO) guideline of 45 µg/m ³ , and the highest concentrations of Cu and As, significantly higher than UIZ and UCZ (p < 0.001 and p = 0.015, respectively). The combined application of environmental indices classified UPZ as heavily contaminated by Cu and As, with extreme enrichment (enrichment factor, EF Cu = 2432; EF As = 2393) and considerable ecological risk (potential ecological risk, PER = 384). Back-trajectory analysis (HYSPLIT) revealed that the highest concentration episodes at UPZ coincided with air masses arriving from continental sectors at 1000 m altitude, including the direction of the local smelter. Health risk assessment identified significant non-carcinogenic risk exclusively at UPZ (hazard index, HI = 7.2), dominated by Cu (89%), while the incremental lifetime carcinogenic risk (ILCR) from As remained at acceptable levels. These findings are applicable to industrialised coastal cities with port, metallurgical, and urban activities in developing countries.

Drylands are spatially discontinuous, so inventories confined to a few localities may poorly represent regional biodiversity. We assessed lichen richness and composition across eight sectors spanning coastal fog oases and high-Andean shrublands in southern Peru. Surveys conducted from 2020 to 2022 used the same numbers of stations and sampling units per sector, with sector as the principal ecological unit. We recorded 53 morphotaxa; one coastal sector yielded no detections, whereas the richest occupied sector contained 21. Among the seven occupied sectors, multisite Jaccard dissimilarity was high (βjac = 0.936) and dominated by turnover (βjtu = 0.911; 97.3%) rather than nestedness-resultant dissimilarity (βjne = 0.025). Exhaustive enumeration of all 127 non-empty combinations showed that the smallest favourable combinations reaching 80%, 90% and 95% of the observed morphotaxon pool contained four, five and six sectors, respectively; all seven were required for 100%. These were retrospective best-case minima: four-sector combinations represented 39.6–86.8% of the pool and six-sector combinations represented 60.4–98.1%, so the poorest four-sector combination performed no better than the single richest sector. No sector count below seven guaranteed even 80% coverage across all possible selections. Dependence on sector number and identity persisted at confirmed-species and genus resolutions. Strong spatial turnover therefore made inventory representativeness contingent on which sectors, as well as how many, were sampled, supporting multisector inventory and monitoring designs rather than reliance on a few locally rich sites.

Legacy static-chamber records from wastewater stabilization ponds may retain information on gas buildup but can be unsuitable for flux estimation when closures exceed conventional protocols. We applied a reproducible screening workflow to chamber-headspace records of CH₄, N₂O and CO₂ from the Omo wastewater treatment plant, southern Peru (1,410 m). The workflow applies seven sequential gates covering raw signal, quality control, chamber state, temporal design, thresholds, replication and covariate timing; the first five are flux-critical. Three campaigns (August–October 2022) yielded 36 observations per gas from one sampled cell per pond stage at post-closure days 1, 3, 7 and 9, which are temporal repeats, not spatial replicates. The audit found that 1 Hz traces, calibration and leak-test records and purge windows were not retained, that closures of 1–9 d were approximately 48–432 times longer than a 30-min protocol, and that 52.8% of ΔCO₂ fell below the operational threshold. Post-closure time was the strongest predictor of ΔCH₄, ΔN₂O and ΔCO₂ (standardized β = 0.830, 0.741 and 0.541; all p < 0.001), no Tukey-adjusted cell contrast was significant, and pond cell and organic load were aliased. The records are therefore classified as chamber-headspace accumulation, not validated fluxes. The transferable contribution is the workflow itself.

Total mercury (THg) was quantified in dorsal muscle tissue of 12 blue sharks (Prionace glauca; 6 males, 6 females; total length 167–230 cm) landed at the artisanal fishing port of Ilo, southern Peru, on 12 October 2021. THg was determined by cold-vapour atomic absorption spectrometry (CV-AAS) following NOM-117-SSA1-1994 at an ISO/IEC 17025-accredited laboratory. Mean THg was 0.156 ± 0.102 mg kg⁻¹ wet weight (range 0.021–0.330 mg kg⁻¹), and all samples remained below the maximum permissible concentration (MPC = 1.0 mg kg⁻¹ w.w.) established by FAO/WHO, SANIPES and the European Union. THg correlated positively with total length (Pearson r = 0.768, p = 0.003), consistent with size-dependent bioaccumulation. Females showed higher mean THg concentrations than males; however, this difference was not statistically significant at the present sample size (n = 12), and should therefore be interpreted as suggestive rather than conclusive. Under US EPA default consumption assumptions, the Target Hazard Quotient marginally exceeded unity (THQ = 1.12) while the Estimated Weekly Intake remained below the Provisional Tolerable Weekly Intake for all population groups (19.6% of PTWI for adults; 52.6% for pregnant women). These results provide the first local quantitative baseline of total mercury concentrations in P. glauca from the artisanal port of Ilo, representing an initial reference dataset for future monitoring efforts. Although THg levels were below regulatory limits, the THQ slightly exceeding unity under conservative default assumptions indicates a potential concern for vulnerable consumers and supports targeted dietary guidance and continued monitoring.